Telephone-exchange switching mechanism.



0. F. FORSBERGQ TELEPHONE EXCHANGE SWITCHING MECHANISM.

APPLICATION FILED FEB-5.1915.

lllll Patented Jan. 8; 1918.

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O. F. FOIISBERG. TELEPHONE EXCHANGE SWITCHING MECHANISM.

' APPLICATION FILED FEB. 5. 1915.

1,252,420. Patented Jan. 8,1918.

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TELEPHONE EXCHANGE SWITCHING MECHANISM.

APPLICATION FILED FEB. 5. 1915.

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0,97% $02753, Oscar E Forsberq.

UNITED STATES PATENT OFFICE.

OSCAR F. FORSBERG, OF YONKERS, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SWITCHING MECHANISM.

To'aZZ whom it may concern:

Be it known that I, OSCAR F. Fonsenne, a. citizen of the United States, residing at Yonkers, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Telephone- Exchange Switching Mechanism, of which the following isa full, clear, concise, and exact description.

This invention relates to panel type automatic switches employed to interconnect telephone lines. In this type of switch the lme terminals are multipled across a flat-faced bank to be accessible to brushes mounted upon carriers traveling thereover.

One of the objects is to' provide a simple and eflicient switch of this type, wherein connectionmay be made with any terminal therein by a relatively slight movement of the brush carried.

Another object is to provide an automatic switch structure which may, with slight alterations, be used either as a line finder, a

selector, or a connector.

In accordance with this invention, each of the vertical rows of terminals of the panel is divided into sections and a brush is provided for each section, the brushes serving a given row being arranged spirally upon a common carrier. Eachcarrier may be given a rotary movement by suitable electromagneticmeans to position a predetermined brush in operative relation to its section or division, and a vertical movement to cause said brush to wipe over the terminals of said division to connect with a particular one thereof.

When the structure is used to connect calling lines to connecting circuits, that is to say as a line finder, the brush carriers are so arranged that each group of lines, represented by terminals multipled across the panel, has a brush carrier normally apportioned to it with one of its brushes in operative relation to multiples of said terminals By virtue of this arrangement, upon the initiation of a call in any group, a brush of the carrier apportioned thereto will be in position to wipe over said terminals in search of the calling line, no rotary movement of the carrier be ing necessary. It will be understood however that all the carriers are accessible to all i the line groups, and if the brush carrier apportioned to any line group is busy when a call comes in from its group, the carrier set- Specification of Letters Patent.

Patented Jan. 8, 1918.

Application filed February 5, 1915. Serial No. 6,302.

in motion to find the line initiating the call must first be rotated to position the one of .its brushes serving such group below the multiples thereof 1n the row served by it, whereupon it is elevated to make connection with the calling line.

The means for imparting rotary move-- movement to cause the selected brush to con- 7 nect with a particular line in the group. Up'on'the beginning of the upward travel of the carrier, as it moves out of-engagement with the said spring-restored member, means is rendered active to lock said member.

When the carrier is released by the with-- drawal of the holding pawl and rengages said spring-restored member as it reaches its lowermost position, said member is unlockedand rotates the carrier to its normal position.

The motion of the spring-restored rotary driving member may be communicated to the carrier by gears, which intermesh only in the lowermost position of the carrier, and the means for locking the rotary member to prevent it from being restored when displaced may consist of a fiat spring,.'which rises to thrust a. projection thereof between the teeth of the gear of the rotary driving member upon the first vertical movement of the carrier. Thecarrier, upon the end of its reverse vertical movement, after being released, depresses this spring which withdraws its projection from between the teeth of the driving gear, whereupon the driving member, by means of the gears referred to,

rotates the carrier to normal position.

One of the advantages of this construction lies in the fact that the carrier is absolutely .there is also relatively little friction to retard the dropping of the carrier upon its release.

Another advantage of this construction as applied to the switch structure when used to These brushes therefore being free of Fig. 1;

associate calling lines with connecting circuits, lies in the facility with which the carriers may be arranged on the panel so that the varying relation ofthe brushes to the line" groups in the different finder mechanisms' above described may be secured, this being determined by the teeth which normallyintermesh in the two gears. i

A feature of the invention is the provision of means for preventing. the brush carrier from rebounding upon reaching its lowermost position. The means for accomplishing this result may consist of a spring member normally retracted out of the path of movement of the carrier and moved by the release means for the switch into the path of a rim on thelower end of said carrier. Thus. as the carrier reaches its lowermost position, the rim slips over said spring whereby-the carrier is locked. This spring. member is immediately withdrawn upon the denergization of the releasemagnet-to free the carrier for use in establishing another connection.

Another feature of the invention is the provision of an improved steering switch for preparing circuits at the proper times for the control of the automatic switches.

Still another feature of the invention is the provision of an improved set of brushes or wipers, for engaging the sets of terminals of the panel, wh ch is cheap to manufacture and eflicient in operation.

A further feature involves the provision of a frame punched out of sheet metal to cheapen the cost of the switch and the, means for preventing such relatively light material from vibrating with the armatures of the stepping magnets, since it has been found that such vibration interferes with the operation of the switch.

Referring to the drawings, Figure 1 is a perspectlve View of the lower part of an automatic finder switch embodying my invention' 1 2 is a sectional view on the line 22 Fig. 3 is a sectionaljview on the line 33 of Fig. 1;

Fig. 4 is a detail view of the brush rod rotating means Fig. 5 is an enlarged view of the steering or controlling switch for the automatic sei lector switch Fig. 6 is a side. view partly in section, of

the upper portion of a finder switch mechanisin and a connector switch mechanism, and the, common panel, over wh1ch they travel, i

the upper and-lower, and part of'an intermediate section of such panel being shown, with the cooperating sets. of brushes;

Fig. 7 is a section on line 7+7 of Fig. 6, showing the switch at the top of the finder, which chooses the group containing the call- Fig. 8 is a section on line 8-8 of Fig. 6, the positions of the other sets of brushes being indicated by dotted lines;

Fig. 9 is a detail perspective of a set of brushes and Fig. 10 is a detail perspective of a modified form .of brush set.

Fig. 11 is'a detail showing the manner of attaching'a finder or connector unit to the frame.

The terminal bank is of the type shown in United States Patent No. 1,098,529. It is made up of strips of metal 25 and interposed insulating strips 26 (Fig. 8). Each of the metallic strips has ears or lugs projecting from opposite faces of the panel and adapted to be wiped over by the brushes of the automatic switches. Three of these strips 25 are apportioned to each line. A set of terminals 27, 2 8, 29, one belonging to each of three adjacentstrips, individual to a given line, is adapted to be engaged by a set of brushes 34, 35, 36, of a line finder brush rod 48 to connect with said line on one side of thepanel as a calling line, and the opposite lugs 30, 31, 32 of the same strips are adapted to be engaged by a simi- V lar set of brushes 38, 39, 40 of a connector shown, the line and test terminals of a hundred lines, suitably mounted between cross bars 123, 124. The panel is divided horizontally by metal bars 42 into ten divisions of ten each. Thus, each vertical row, containing the sets of terminals of one hundred lines, is divided on. both sides of the panel into ten sections. Each section is served by a set of brushes (Fig. 6). The sets of brushes 161, 162, 163, serving a vertical row of terminals on the finder side, are mounted upon the rod 48.

The sets 164, 165- 166, serving a vertical row on the connector side,

are mounted upon the rod 51. These rods reciprocate in suitable bearings in cross bar 124: and in plates 125, 126attached to cross bar 123. The brushes of the finder rod 48 are multipled together by conductors 149, and those of the connector rod 51 by conductors 150; As may be seen from Figs. 6 and 8, the sets of brushes of both the finder and connector rods--48 and 51 are spirally arranged thereon. Each rod may be rotated to position the proper set of brushes below any section of the vertical row served by said rod. It is then elevated to cause the set of brushes so selected to wipe over the sets I of terminalsof such section of the row tois such as to permit the brushes of the finder and connector mechanisms to rotate without hindrance by the fixed terminals. The brush rods 48 of the finder mechanisms are preferably so arranged that each group of lines has a set of brushes on one of the rods 48 assigned thereto normally just below multiples of the strips 25, wherein said lines terminate. Thus, since only a vertical movement of the rod assigned to a group is necessary to connect with any ofthe multiple sets of terminals of said group,.connection may be quickly made to any calling line in any group. Should the finder rod 48 nor mally assigned to any group be busy, however, another rod 48 will be set in motion and given a primary rotary motion to position the brush serving the section of the row containing the multiples of the group containing the calling line below said section, and thereafter a secondary vertical movement to connect with the set of calling line terminals in said section, it being understood that the finder rods 48 are accessible to all the lines. For this purpose a switch 52 is associated with each finder mechanism. Each group of lines is representedv on this switch by a metallic segment 53. These segments are adapted to be wiped over by an arm 54, mounted upon but insulated fro-m the brush rod 48. Normally, the-brush 54 rests on the segment 53 of its own line group.

The initiation of a call therein changes the electrical condition of this segment, which causes a circuit change to be brought about to cause the secondary magnet 64 (Fig. 1) immediately to elevate the rod 48 to connect with the calling line. In case, however, this finder had been takenby a call from another group, the primary magnet 49 (Fig. 1) rotates the carrier 48 until the brush 54 reaches the segment 53 of the group to which the calling line belongs, and whose electrical condition was changed upon the initiation of such call. A circuit change is then brought about to stop such rotary movement. The relation between the brush 54 of the rod 48 and the sets of brushes 161, 162, 163 is such that when said arm has reached the segment in question, the set of brushes on the rod 48 belonging to this line group is positioned just below the section of its row in which multiples of this group of'lines appear. The secondary magnet 64 is then operated to elevate the rod 48 to cause the said set of brushes to wipe over these sets of terminals until that of the calling line is reached, when a circuit change is produced to stop such movement, whereby the calling lineis connected through this finder to a connector mechanism, which is then con trolled to extend the connection to the wanted line. or in case of a large exchange first through a series of selectors. The connector associated wit-h this finder may be one of therefrom at thetop, where it is connected to said brush.

A more detailed description of the structure will now be given. Since the lower part of both finder and connector mechanisms'are substantially alike, only'that of the finder is shown in Fig. 1. A description of this portion of the, switch will serve for the corresponding partof the connector.

Referring now to Figs 1, 2 and 4, the brush rod 48 is provided near-its'lower end with a gear wheel 61. This gear wheel in: termeshes with a gear wheel '60 of a rotatable member 58, mounted upon inturned portions 155, 79 of the frame plate 127. The member 58 is rotated by the pawl 56 of the armature 57 of a magnet 49 mounted upon the frame plate 127, and suchmotion is transmitted by the gears 60, 61 t0 the rod 48. When the desired amount of rotary movement has been givmthe rod 48 is held.

in such off-normal rotary position against the tension of a spring 67 by a dog 68, carried by a plate 74, pivoted on a rod 131 carried on lugs156, 157 on the frame plate 127.

It is then elevated by the pawl 62 of the armature 63 of a magnet 64 engaging ratchet 55, said magnet being mounted on lu'gs 129 of plates 127,128. Upon the beginnin of a 1 the upward movement of the rod 48, a spring 65, anchored at one end to plate 79 and held against such plate in the lowermost position of the rod by a hub 78 thereon, moves upwardly, a pin 66 thereon entering the notch between the teeth of the gear wheel 60 at this time above it.

The carrier 48 is held in its elevated position by a dog 69 engaging ratchet 55, said dog being formed of an arm of a plate 77, pivoted 0n rod 131. A

4 Upon the operation of the release magnet 71, a roller 72 carried by an arm 73 projectwith the arm 76 of the plate 77 an arm of said plate terminating in the dog 69 of the vertical ratchet 55. The withdrawal of the dog 69 permits the rod 48 to drop.

When the brush rod 48 reaches its lowermost position. the hub 78 thereon presses the spring 65 against its mounting plate 79. The consequent withdrawal of the pin 66 from the gear wheel permits the spring 67 to rotate the member 58, whereupon the gear wheel 60 rotates the brushrod 48-until a lug 86 on the member 58 engagesa lug 87 on the lug 155 of the frame plate 127, this being the normal position of the carrier. The apparatus is now in normal position.

By virtue of the construction just described, since the brush rod 48 is freefrom tension, the wipers 34, 35, 36, which have a tendency to press inwardly, automatically take care of any inaccuracies in alinement of the rows of fixed terminals 27, 2,8, 29, and also all danger of the rod not dropping fully to its lowermost position, due to friction, when released, is greatly reduced, if not eliminated. An arm 80 carrying an insulating roller 167, is fixed to the member 58, and as said member moves away from normal position, actuates springs 82 mounted on a plate 132 secured to extension 79 of plate 127 (Fig. 3). A pair of springs 84 are also actuated byithe carrier 48. as it be gins to move upwardly.

In order to prevent the brush rod 48 from rebounding, upon reaching its lowermost position, an angular spring 141 extends downwardly from the arm 73 of the armature 70 of the magnet 71, and is adapted to lock the rod momentarily as it reaches its lowermost position. The release magnet 71 when once energized, is maintained energized until the brush rod 48 has reached ts normal position. Thus, when the rod drops, upon the withdrawal of the dog 69 from the ratchet 55, the end of the spring 141 passes over the rim 142 on the lower end of said rod, and slips in behind it to prevent the rod from rebounding. Upon the rod reaching its normal position, the retractive movement of the armature 70 withdraws said spring.

When the switches are'installed or when it is desired to change the relation of the brushes of a carrier 48 to the terminal sections of the row they serve, it is only necessaryto raise the rod 48, when such rod may be rotated to the desired point and lowered so that the gears 60, 61 reengage.

In order to avoid the necessity of periodically oiling the bearings for the carrier 48, a bushing of Babbitt metal and graphite is provided for each of the bearings of the brush rods; that of the upper bearing is designated 159 (Fig. 6).

Referring now to Fig. 9, when the brushes are not in contact with the terminals, the

. movement of the inner sprjngs 35, which are in effect one brush, is limited by the shoulders 109, 110 ofan insulating member 111, carried upon an arm 112, secured to the brush rod 48. The inward movement of the outer springs 34, 36 is' limited by the ends-of the projections 170, 171 of the member 111,

which extend through openings in the inner springs 35. 'Thus it will be seen that the brushes 34, 35, 36 are movable independently of each other, and automatically take care of any irregularities in alinement of the rows of terminals.

Each set of brushes is made in unit form and is readily mounted upon and removed from the rod 48. Each unit comprises a T- shaped punched mounting plate 115. The

' brushes are secured by screws 114 on one arm 113 of said plate 115; another arm 112 carries the member 111 referred to. The lower arm 116 encircles the rod and is adjustable vertically and rotatably thereon, a screw 117 passing through the ears 118 thereof and thus clamping the plate 115 to the rod. I

\ Fig. 10 shows a modified form' of-brush this switch is to prepare circuits at the proper times, for the control of the automatic switches described. The steering switch carries a set of brushes 89, adapted to wipe over a series of contacts 104, arranged in an are on an arm 108, integral with pole piece 94 of a magnet 96 mounted between plates 127, 128 (Fig. 1). These brushes are insulated from each other and pivoted on a pin, 91 mounted on lug 92, also integral with the pole piece 94. .They are held under tension by a spring-88 attached at one end to the outer ends of the brushes, and at its other end to a fixed lug 172. These springs are released step by step under the influence of spring 88 by an escapement mechanism controlled by the armature of the magnet 96. This escapement mechanism comprises a member 97 (Figs. 1

and 5) notched on both sides and formed out of a U-shapedmember 173,'and a Y air I of holding pawls 98 99 pivoted on the pivot pin 100 of the armature 95 of magnet 96.

These two pawls tend to move together under the influence of a spring 102,. In the normal positionof thesteering switch, the

pawl .99 is held by spring 102 in engagement with the second tooth 103 of the right hand side of the member 97, as shown in Fig. 5.

In this position'the brushes 89 are in contact with the first set of contacts ofthe bank The attraction of the armature 95 moves pawl 99 out of engagement with tooth 103, whereup on thegspring 88 moves the brushes into contactwith the second set of the bank of contacts 104. The brushes are stopped on the second set by the pawl 98, engaging tooth 105. The armature in its retractive movement moves the pawl 98 out of engagement with tooth 105, and the spring 88 moves the brushes to the third set of contacts, the pawl 99 catching the tooth 106 and holding the brushes on said set. This switch, as shown in Fig. 1, is restored by an extension of the armature 70 of the release magnet 71, engaging a pin 107 of the member 173. The number and arrangement of the teeth may be varied to suit the circuit requirements. 7

Mounting the pawls 98, 99 upon the pin 100, upon which the armature is pivoted, prevents any sliding motion between the armature and either pawl when the armature The plates 127, 128 of the selectors (Fig..-

1) are punchedout of sheet metal to reduce the cost of the structure. These plates are fastened at their lower ends by screws 133 to a support 135, which is in turn fastened by a bolt 168 to cross bar 144, The plates 127 128 are fastened together at their upper ends by an angle piece 136, one side only, of

which is visible in Fig. 1. The brush rod 48 has a bearing in this piece 136. The

plates 127, 128 are provided with lugs, that' 143 of plate 128 being visible in Fig. 1. These lugs enter openings in cross-bar 124 which. is cut away at the front edge to receive angle piece 136 and the brush rod. The entire structure, comprising the plates 127, 128 and the parts they support,

' together with the part 135, is a unit. and is attached to the cross-bars 124, 144, which extend transversely of the panel, by inserting the lugs 143 into the slots, or openings in cross-bar'124, springs 145, anchordto a bracket 158secured between the plates 127, 128, clamping said plates in position, whereupon the bolt 168 is passed through support 135 and into cross-bar 144. Thus finder and connector mechanisms may be readily attached to and' removed from the anel by merely removingv asingle bolt.- he necessary electricalconnections are antomatically made bythe springs 153. mounted on frame plate 127 engaging springs 154 I mounted-upon cross-bar 144.

In order to'prevent the plates 127, 128 from vibrating, due to the operation of the armatures of the stepping magnets, these plates are tied together by arms 137, 138,

integral with the pole piece 139 of magnet 71, by the pole piece 140 of magnet 64 which bridges lugs 129 of plates 127, 128 and by arms 174 (one only of which is visible) (in Fig. 1) of the pole piece 94 of magnet 96.

What i's claimed is: i .1. An automatic switch having abrush carrier, a spring-restored driving member engaging said carrier, means for operating said driving member ,to rotate the carrier, means for thereafter moving said carrier in the direction of its axis of rotation whereupon it moves out of engagement with said driving member, means for locking said driving member under tension, and means for releasing thesame as the carrier re- 7 engages therewith at the end of its return;

movement.

2. An automatic switch having a. brush carrier provided with a gear wheel, a springrestored driving member therefor having a gear wheel, said gear wheel meshing with the gear wheel on said carrier, amagnet for rotating said member, means for thereafter moving said carrier in the direction of its axis of rotation, whereupon said gears move out of engagement, and means thereupon rendered operative for'locking said driving member, under tension and rendered inoperative when said gears rengagempon the return movement'of the carrier.

3. An automatic switch having a brush carrier provided with a gear wheel, a spring restored driving member having a ratchet wheel and a gear wheel, said gear wheel meshing with the gear wheel on said carrier, a magnet, a pawl therefor adapted to engage said ratchet wheel to rotate said member,-means for thereafter elevating said carr1er whereupon sa1d gears move out of engagement, a flat sprlng mamtamed depressed by said carrier when in its lowermost position and having a toothadapted to rise between teeth of the gear on said driving member to lock the same when; the carrienis elevated, said tooth being removed therefrom when said earsre'ngage upon the return movement 0' the'carrier. I v

4. In a steering switch, the; combination with a frame, terminals arranged in an arc thereon, a set of contact brushes pivoted intermediat their ends and. ,adaptedto wipe over said terminals, a spring attached at one end to the frame and at its other end to said brushes to place the same .under tension, ,an .cscapement for permitting said spring to move sa1d brushes successively over said terminals,- and amagnet for operating said escapement.

5. In a steering swltch, the combination with a frame, terminals arranged in an arc thereon, a set of contact brushes therefor perforated intermediate their ends, a pivot pin mounted upon said frame and extending through said perforations, a spring attached at one end to the frame and at its other end to said brushes, an escapement for permitting said spring to move said brushes in steps over said terminals, and a magnet for operating said escapement.

6. In a steering switch, the combination with a frame, terminals arranged in an arc thereon, a set of contact brushes therefor perforated intermediate their ends, a pivot pin mounted u on said frame and extending through "said perforations, a spring attached at one end to the contact brushes and at its other end to the frame, an escapement for permitting said spring to move said brushes in steps over said terminals,

said escapement comprising a member piv-,

oted on said pivot pin and having toothed edges and a pair of spring-pressed pawls engagingsaid toothed edges, a magnet and its armature, one of said pawls being removed from engagement w1th.said member upon the movement of said armature in one direction.

7. In a steering switch, the combination with a frame, terminals arranged in an arc thereon, a set of contact brushes perforated intermediate their ends, a pivot pin mounted upon said frame and extending through said perforations, a spring attached at one end to said brushes and at its other. end to. the

- frame, and an escapement for permitting said spring to move said brushes in steps over sald termmals, said escapement consisting of a member pivoted on said pivot pin and having toothed edges and of a pair of spring-pressed pawls engaging said toothed edges, a magnet, an armature there for ada ted to operate said escapement, a pivot pm for said. armature, one of said pawls being removed from engagement with said member upon the movement of said armature in one directionand the other pawl beingremoved upon thereverse movement, whereby said spring advances said brushes, said pawls being mounted'upon the aeaaaeo edges, a magnet, a pole piece therefor, an

armature for said magnet, a pivot pin for said armature, one of said pawls being removed from engagement with. said member upon the movement ofsaid armature in one direction and the other pawl being removed upon the reverse movement, whereby said spring advances said brushes, said pawls being mounted upon the armature pivot pin, lugs integral withsaid pole piece, said pivot pin for the brushesbeing supported on said lugs, a projection also integral with said pole piece, said brushes being carried upon said projection.

9. In a steering switch, the combination with a frame, terminals arranged in-an arc thereon, a set of contact brushes perforated intermediate their ends, a pivot pin mounted upon said frame and extending through said perforations, a spring attached at one end to the frame, and at its other end to said brushes, and an escapement for permitting said spring to move said brushes in steps over said terminals, said escapement consisting of a member pivoted on said pivot pin and having toothed edges and a pair of spring-pressed lever arms engaging said toothed edges, a magnet and its armature,

one of said levers being removed from engagement with said member upon the movement of said armature in one direction and the other "upon the reverse movement, said levers being made angular in form and of flexible material, whereby they are adjustable with regard to said toothed member.

L 10. In an automatic switch wherein the terminals are arranged in sets in a panel, the combination with a set of brushes comprising a pair of inner and a pair' of outer springs, acarrier to which said brushes are secured at one end, an arm projecting from said carrier, a member thereon having shoulders limiting the movement of the inner springs toward each other and having projections extending through openings in said inner springs against which the outer springs abut.

11. In an automatic switch wherein the terminals are assembled in sets in a panel, the combination with sets of brushes adapted to wipe over said contacts, a carrier, a T-shaped piece, said brushes being mounted upon one of the arms of said piece, a posi tioning member for the' free ends of said brushes mounted upon the opposite arm, the a leg ofsaid piece forming a-clamp by means of which the said member is positioned on the rod. 1

12. In an automatic switch, the combina-' tion with a frame consisting of sheet metal plates, means for supporting said plates, a

steppingmagnet mounted on and lying between said plates, a stepping pawl therefor, a brush carr er adapted to be actuated by said pav vl, and means for bracing said plates In witness whereof, I hereunto subscribe to prevent them from yibrating upon the my name this 4th day of February, A. D.

operation of said armature. h Y b 1915.

13. nan automatic switch t e com ina- 5 tion with a frame comprisihg a pair of I OSCAR EORSBERG' plates, of a brush carrier, and a driving Witnes'ses: magnet therefor having projecting portions E. EDLER, secured to each of the plates. K. L. STAHL. 

